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392 w/ported heads and Cam

23K views 36 replies 14 participants last post by  Fawls 
#1 · (Edited)
Been meaning to post this for a while, been busy working, racing and getting some work done on the 392. Thought I should share for anyone interested or thinking about doing the same.


Had the work done by JMB Performance out of Hillsboro MO

Custom 279 Camshaft
Ported Heads and intake
1 7/8 Long Tubes w/catted mids
Hemifever tuned

Baseline Dyno was 390hp/380tq, after was 475hp/447tq for a gain of 85hp/67tq
I think the baseline was low as the 392 should be about 415-420 stock. Regardless it’s the increase we are looking for, not the actual numbers. Both dynos were early July when it was 105 degrees out. That being said I should be a little over 500whp

“the track doesn’t lie…” lol.

Best Track times; Hero runs and averages (why yes I do spreadsheet everything).

· Stock w/street tires

  • Hero 12.591 @ 110.89 (DA 2400)
  • Average 12.836 @ 110.62 (over 9 runs all in May 2017)


· Stock w/radials;

  • Hero 12.38.1 @ 112.19 (DA 2100)
  • Average 12.549 @ 111.18 (over 9 runs all in June 2017)


· Stock w/Hellcat air box;

  • Hero 12.248 @ 112.55 (DA 415)
  • Average 12.502 @ 112.06 (over 58 runs June 17 to Oct 17)


· Stock w/ tune;

  • Hero 12.101 @ 114.16 (DA 305)
  • Average 12.294 @ 112.64 (over 44 runs April 18 to May 18)


· Stock w/180 t-stat and tune

  • Hero 12.129 @115.06 (DA 2600)
  • Average 12.24 @ 112.92 (over 10 runs June 18)


· After everything else;

  • Hero 11.69 @ 116.24 (DA 2400)
  • Average 11.874 @ 115.64 (only 8 runs so far in the hot and humid July)

Overall I’m happy with the build, she’s faster, has a nice lope and screams under WOT. Feel free to ask any questions, will be happy to answer if I can.

Couple of videos of some 11 second runs;

https://youtu.be/zZmSEMPVvpg
https://youtu.be/9JSg4M46Pn4 (thanks to @STLSpeed for the awesome Video, this was the view from his Hellcat. I just managed a better RT and 60ft. MT’s > Nittos)


 
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#4 ·
Nice! Sounds like a good improvement over stock. How is the street-ability with the A8 and cam? Is it a little laggy from a stop?
 
#8 ·
I hate to say it, but these are really not the cars to mod. They are VERY expensive to mod for small gains. If you did this on a 6th gen camaro, you'd be making 500rwhp for a third of the cost. SUCKs. But nice numbers. I bet you are $3k into it if you did the install yourself. Not trying to be a negative nancy. I have contemplated getting rid of my SCAT for the HC because of this.
 
#18 · (Edited)
I absolutely disagree they don't respond to mods. They respond to the correct mods.

I'm about 100 rwhp over stock N/A.

The 6.4L is superior to the 6.2L LT1.... this isn't debatable. The 6.2L needs 11.5:1 compression and a 87mm TB just to make 455 h.p.

The 6.4L has wonderful heads from the factory (superior to the LT1) and are even better when ported. They can take full advantage of aftermarket cams.

Where people drop the ball with the 6.4L is with the tune. Good GM tuners are far easier to find than good Mopar tuners.

550 rwhp N/A is achievable for a 6.4L and you would still have a good,streetable car. Now... it would take good tuning and the right recipe of parts.

I made 520 rwhp and this was with the car drinking oil on the dyno from the manifold. With my current setup / tune on E85 or race fuel (VP109), I wouldn't be shocked to see it hit 540 rwhp. My cam also isn't really that aggressive.... 224/230 112.5.

I could have probably dropped the LSA down to 110 and went with a 228/236 and traded some street manners for more power.
 
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#23 ·
Yea, but you're still only driving a Chevy or a Ford as the case may be...no thanks.


Exactly. I’ll pay a little more to not drive a ford or chevy. Or spray a 125 shot on an otherwise stock 6.4 (tuned and plugs of course) and be done with it at the track (and any street shenanigans). Of course you will need some good rear tires and wheels but you will run great times and at all the same price a ford or chevy guy would have to pay.
(But cam/heads are also fun)


Sent from my iPhone using Tapatalk
 
#11 ·
It comes down to what has more perceived value in the owner's eyes. If everyone valued the cheapest cost to go fast then everyone would drive the same exact car, probably a gutted 1980's Camaro with a crate SBC. Sometimes brand loyalty is the driving factor, sometimes heritage is. Sometimes simply being different holds more value than cost vs speed.

Personally, I love the look of my new TA 392 so much, I knew I was going to buy it just based off of 1) looks alone 2) its a Mopar 3) it really is designed in the style and spirit of the original Challenger TA. And I knew I was going to buy it regardless if the seats felt like poo or if the engine is unreliable. I didn't even need to test drive it to decide. At this point I simply don't care if the entire car ends up being a piece of junk because all that means I will do, is gut all the electronics, put a crate 572 in it with an old manual trans or such... and in my eyes I would still be driving the most badass Mopar I've ever owned.

Money IS an object... its an object I blow to get what I want. :grin2:
 
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#20 ·
What is the LSA on the cam? You have some more torque left in the tune. There are some tricks in the cam tables that might help.

I agree your pushing 500 or so. You'd also be looking at low 11's in really good air.

Trust me... the key is the cam tables.
 
#28 ·


Build or Buy?

I know which I prefer......oh and if you think the Demon is FASTER because of that terminal speed......think again. The Cuda Driver is running different classes and taking down slower cars by jumping 'em and then slamming the brakes to squeeze in the win at the line without going under the wire and losing by default........this guy was so good in the 1320 video that this was pealed out of........it was just astounding. The Purple Cuda is a 9.30 second car when run to it's limit.
 
#31 ·
****** UPDATE ******

So after some disappointing runs (11.8) in near perfect DA, plus some smoke out of the exhaust it turns out that a blew a piston. Dropped new ones in, got the car back and it ran like trash for about 4 weeks while we worked on the tune. The shop saying it was tune related and the tuner saying it appeared to be mechanical. The shop I was not happy with… the tuner (Sean at Hemifever) was great to work with and did his best.

Long story short, I ended up putting the stock came back on and selling her. Had to get out while the getting was good.

I’ve seen a lot of modded Scats and 392’s so I know it can be done, but anyone thinking about modding the 6.4 just beware that things can go south quick, and it’ll take a lot of down time.

Overall an expensive lesson learned, but you can find me over on hellcat.org now (STL376)
 
#33 ·
Honesty?

I'm not especially surprised by your experience.

It's not as if the build up of older cars didn't fall on their face sometimes too when seeking out big power gains.

New cars with all the tech under the hood and computer controls......add so very much more complexity and a whole raft of things that must match up perfectly. When they don't it's a whole lot tougher to figure out why the plan on paper and in theory didn't work as well once in place under the hood. Straightening out the matter is a bigger deal too.

We're a long way from the Lawn mower tech of the days when if it had gas in the carb and a spark it had to run.

A problem engine or combination of parts? I've been through this too.....many of us have.

With the older rides though pulling the motor and tearing it down or just replacing things like a cam that didn't work.....easy/peasy. Hours..... not days and weeks to fix and hassle with.

I'm in total agreement with your new path.

If it's a daily driver, it's got to get you to work and the drag strip?

It's hard to beat the idea of a Hell Cat with a warranty vs. building up an immediately warranty VOIDED 392.
 
#35 ·
Interesting read -
 
#37 ·
Sorry to hear about your piston. It’s definitely no secret a bad tune, even on an NA 392 will kill the bottom end. There was a blown na 392 at the shop I use when I dropped my car off. Even still , I’ll build my low payment low insurance 392/426 to its fullest:) here’s where she is now....... https://youtu.be/8RUde66dz4E


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Sounds awesome, I'm jelly!
 
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